Numerical Calculation of Pressure Fluctuations in the Volute of a Centrifugal Fan

Ballesteros-Tajadura, Rafael; Velarde-Suáréz, Sandra; Hurtado-Cruz, Juan Pablo; Santolaria-Morros, Carlos

doi:10.1115/1.2170121

Cited by 46 publications

(28 citation statements)

References 7 publications

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“…CFD technology has been proven to be a very useful tool in the analysis of the internal flow of turbomachinery both in design and performance prediction, and widely employed in simulating the fully 3-D unsteady flow in centrifugal turbomachinery [3,10,14,16]. It can present detailed flow information which is difficult to obtain through experimental measurements.…”

Section: Simulations Of Internal Flowsmentioning

confidence: 99%

“…The rate-of-deformation tensor of fluid is defined as (3) Due to the low pressure rise, we further regarded the flow as isothermal. Since the flow in the centrifugal fan is typically three-dimensional turbulent, it is appropriate to solve the unsteady Reynolds averaged Navier-Stokes equations (URANS) economically without loss of resolving the main characteristics of flow fields such as mean pressure fluctuations.…”

Section: Simulations Of Internal Flowsmentioning

confidence: 99%

“…without taking the casing scattering effect into account, could also be found in Refs. [3] and [25]. Cai et al [6] studied both the tonal casing noise and blade noise of the same fan as in Ref.…”

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confidence: 99%

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Study of the Tonal Casing Noise of a Centrifugal Fan at the Blade Passing Frequency. Part I. Aeroacoustics

Xiao

2010

Journal of Low Frequency Noise, Vibration and Active Control

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This paper is concerned with the simulation of the unsteady turbulent flow and the aerodynamic tonal noise due to pressure fluctuations on the casing wall. Three-dimensional numerical simulations of the complete unsteady flow on the whole impeller-volute configuration were carried out using computational fluid dynamics (CFD) techniques. Pressure fluctuations on the casing wall were obtained, and the blade passing frequency (BPF) component was extracted to be modeled as the dipole source term of the wave equation. In a companion paper, the pressure fluctuations served as the external excitation to the casing vibration. Multi-domain direct boundary element method (BEM) was used to simulate the noise radiation with two domains representing the interior and exterior fields of the volute respectively, in order to take account of the sound scattering effect by the volute casing. Results showed that the dipole on the volute tongue surface was the most dominant noise source of the fan. Slopingedge volute tongue was introduced to reduce BPF noise radiation through phase cancellation between the dipole sources over the volute tongue.Key words: centrifugal fan; casing; blade passing frequency; acoustic dipole source INTRODUCTIONCentrifugal fans, pumps and compressors are widely employed for industrial and civilian use. Their noise has been studied extensively, and is customarily classified into aerodynamic noise and structural noise. The noise spectrum of a centrifugal fan is characterized by broadband noise with pronounced discrete frequency tones. The broadband component arises from random fluctuations in pressure over a wide range of frequencies, and is associated with turbulent flow in the inlet stream, in the boundary layer, and the wake behind the blade. The prevailing discrete frequency tones are caused by the interaction between the mean air flow leaving the impeller and the fan casing. Among them, the BPF component is usually the most noticeable. This paper focuses on the numerical study of the BPF casing aerodynamic noise of a centrifugal fan through CFD and computational aeroacoutics (CAA). The BPF component of the noise spectra about this centrifugal overwhelmingly dominated other frequencies. Its companion paper studies the BPF casing vibration-induced noise. CAA is concerned with the prediction of the aerodynamic sound source and the transmission of the generated sound. The approaches used to solve the aeroacoustic problems can be generally classified into two broad categories: direct computation and indirect, or hybrid, computation. The direct approach computes the sound together with its fluid dynamic source field by solving the compressible flow equations. In a hybrid approach, the computation of flow is decoupled from the computation of sound, which can be done in a post-processing step based on an aeroacoustic theory [24]. Although recent advances in CFD and in computer technology have made the

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Section: Simulations Of Internal Flowsmentioning

confidence: 99%

Section: Simulations Of Internal Flowsmentioning

confidence: 99%

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Study of the Tonal Casing Noise of a Centrifugal Fan at the Blade Passing Frequency. Part I. Aeroacoustics

Xiao

2010

Journal of Low Frequency Noise, Vibration and Active Control

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“…According to Figure 2, about 6.7 × 10 6 cells grid was considered sufficient to ensure mesh independence for the three-dimensional configuration. In order to use the formula to describe the flow in the logarithmic law layer [5], the dimensionless parameter + is introduced:…”

Section: Manufacturing (Icem)mentioning

confidence: 99%

Prediction and Reduction of Aerodynamic Noise of the Multiblade Centrifugal Fan

Zhou

Wang

2014

Advances in Mechanical Engineering

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An aerodynamic and aeroacoustic investigation of the multiblade centrifugal fan is proposed in this paper, and a hybrid technique of combining flow field calculation and acoustic analysis is applied to solve the aeroacoustic problem of multiblade centrifugal fan. The unsteady flow field of the multiblade centrifugal fan is predicted by solving the incompressible Reynolds-averaged NavierStokes (RANS) equations with conventional computing techniques for fluid dynamics. The principal noise source induced is extracted from the calculation of the flow field by using acoustic principles, and the modeled sources on inner and outer surfaces of the volute are calculated with multiregional boundary element method (BEM). Through qualitative analysis, the sound pressure amplitude distribution of the multiblade centrifugal fan in near field is given and the sound pressure level (SPL) spectrum diagram of monitoring points in far field is obtained. Based on the analysis results, the volute tongue structure is adjusted and then a lownoise design for the centrifugal fan is proposed. The comparison of noise tests shows the noise reduction of improved fan model is more obvious, which is in good agreement with the prediction using the hybrid techniques.

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“…These confined configurations imply important interactions between the impeller and the volute casing. This is a key concern for noise generation in centrifugal fans, which is often dominated by tones at the blade passing frequency and its higher harmonics [Ballesteros-Tajadura et al, 2006] [Younsi et al, 2008]. Due to the increasingly strict environmental restrictions and human comfort requirements, this aerodynamic noise generated by blowers is receiving more research attention, both experimentally and numerically.…”

Section: Introductionmentioning

confidence: 99%

Toward a near-field CAA-CFD coupling approach: Application to a centrifugal blower

Foulquié²,

Khelladi

et al. 2017

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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Centrifugal blowers are widely used in heating, ventilation and air-conditioning to generate high mass flow in compact geometries. Confined configurations imply important interactions between the impeller and the volute casing, which causes acoustic tonal noise. This study is focused on the simulation of the noise propagation into a subsonic centrifugal blower. In this confined domain, integral methods in acoustic reach their limits since they do not take into account reflection and diffraction. Instead, this near-field propagation issue is tackled here by the use of a wave propagation operator such as Linearized Perturbed Compressible Equations (LPCE). First, a simple acoustic source model is proposed. Then, sources are extracted from CFD computations. This two kind of sources are experimented as inputs into the propagation operator. Spatial resolution is enforced by a high order finite volume CAA solver (FV-MLS). The moving parts are taken into account through an innovative sliding-mesh approach.

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Numerical Calculation of Pressure Fluctuations in the Volute of a Centrifugal Fan

Cited by 46 publications

References 7 publications

Study of the Tonal Casing Noise of a Centrifugal Fan at the Blade Passing Frequency. Part I. Aeroacoustics

Study of the Tonal Casing Noise of a Centrifugal Fan at the Blade Passing Frequency. Part I. Aeroacoustics

Prediction and Reduction of Aerodynamic Noise of the Multiblade Centrifugal Fan

Toward a near-field CAA-CFD coupling approach: Application to a centrifugal blower

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